Yay, family key's are live: Implemented-In: Tor 0.4.9.1-alpha, Arti 1.4.1 https://gitlab.torproject.org/tpo/core/torspec/-/blob/main/proposals/321-hap...
https://community.torproject.org/relay/setup/post-install/family-ids/ Copy the MyFamilyKey.secret_family_key file into the KeyDir of _every_ _one_ of your relay.
Oooh, damn it. No ansible. Happy copy pasting happy-families ;-)